From nobody Fri Oct 10 08:24:27 2025 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E2A81EF0B9 for ; Mon, 16 Jun 2025 05:15:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750050948; cv=none; b=jB+jFRcDN90Igj/LRcbn7w6nbh9l+MXUU7k1G/edKw7GRU2eSML4N5Kh63PRRR5mX3j2JwTQC997fNKkVz9vOQBGIH/brKeGMjtNxquFH+ji9q4ucNaYlUlbGm0W7QR2CvxMbkfcLNKEYTOFTEUbGhlUvNhVcOGDvpucz4Glrag= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750050948; c=relaxed/simple; bh=oHlVYZzRVwAe+UXK9uHdGLjOLnxQvDDCV87amYBN0F0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=sl4GkFMAIxupJUkbeAyOZ5q6CvFWdiYpF6ge3LxY1IflC4t99zR2ATyw5VpDlE6K8w3narCiT6SkySJATKYk+WiX+PuQwvNCUzrNjy3ewTP6/RjaJZ5Jnt15iJsIgLuZWsLqG3HYH+poT19i8coNLC8l9tyq2PmpfDe81ZbOhp8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Bq/mFvDB; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Bq/mFvDB" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2362e130be8so38695695ad.0 for ; Sun, 15 Jun 2025 22:15:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1750050947; x=1750655747; darn=vger.kernel.org; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=Wsyda4WtQQy5+ceUs120ZRx1vnKpP9F70AgtsBQ2bGg=; b=Bq/mFvDBp5MuA5B5f01iaFZ8r7lO+CttGxvLfyxJY77sONscn+CUCEEhZFtgmW3PT4 UDtNV+G5v522zdaJsJ0w73i4Rr5z8iAgbBcqjI3SMqfIfelVAMB2lgOI4GFVq504PGhL JF8xnVSYKyV/jHMTZPpvMHn6pyXs7CbROvxvMN85eeEu8BzE9OnCSF8Wips3xtun5aOM +j2KoEc4fzsAGjJSTu+0lM3ZLtz05flogTohqYwcUt2uiFBrUHHT6ixeeeYi5R/1n2Ev LFl/zJUsFTMhakkzvvLvFmTRwvOGXRFF8m7umPwuRh4HKtLPJy+6+KQaAwIv1EKTgPXL Nsqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750050947; x=1750655747; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Wsyda4WtQQy5+ceUs120ZRx1vnKpP9F70AgtsBQ2bGg=; b=f8SJ2Wedclc1hcEnkZG1iBZ7copamFTDhym8em/bd28q5W3SLm8ddyvrmM9q19E+uP Eirp5ocvHVFN1pOa4ngTG4/TB1MxqU8+EQGwXrexSwjBuvvfFXY2ueRpi86ldtR7oNgk 2K4QAVzihzMZUt5AYwgLrU+mZGc5j/V4FbSWTbWtCbhZZNgBMbOuN5ydCtJB7Fe909KA KnqkplnCgi4ajvfucniwlz39bR8B5BwyLWS7Eld5+oTWHTPRT0Kr/lHRr8bZqQyXQcXE LvSvBrmWD/XUAeQ5CwMhkDGqxVfrVpltJEyvUTj5SV//Z8Ci4qQLwl+eLBniW4T5SaGj 0i8A== X-Forwarded-Encrypted: i=1; AJvYcCVk9AaEpPhqmuNwqmfbISCU63bsEqZkosl74zRx2wpqAi6kN64qwdoegnFQyQnJS5BNXOM/3IZ3X0oPWEI=@vger.kernel.org X-Gm-Message-State: AOJu0YxbWpYpTvYZmapJynTfPQGD35mVuClgZTW1EznDzV0IDgCmqKDh /W3+I2291/P1xLQOA7Vf1ve6vhNBSMkZljo9oSjnjV769S5qahHZ+jw+zSUFpBkYEy7157OiTh/ wQrwi848Z1g== X-Google-Smtp-Source: AGHT+IGwfWpc//cUVY4b4gWE7CLvuCzE1A8Mm52F41Dmu8y2Xdr19DhW2SlYDWwzD5GvgD+CV+Qi1YzCmNCn X-Received: from plpn20.prod.google.com ([2002:a17:902:9694:b0:235:e1d6:6dd9]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:fc87:b0:234:d1f2:da31 with SMTP id d9443c01a7336-2366b001621mr134870535ad.2.1750050946836; Sun, 15 Jun 2025 22:15:46 -0700 (PDT) Date: Sun, 15 Jun 2025 22:14:55 -0700 In-Reply-To: <20250616051500.1047173-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250616051500.1047173-1-irogers@google.com> X-Mailer: git-send-email 2.50.0.rc2.696.g1fc2a0284f-goog Message-ID: <20250616051500.1047173-11-irogers@google.com> Subject: [PATCH v3 10/15] perf pmu: Tolerate failure to read the type for wellknown PMUs From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , James Clark , Xu Yang , John Garry , "Masami Hiramatsu (Google)" , Howard Chu , Weilin Wang , Thomas Richter , Andi Kleen , Tiezhu Yang , Gautam Menghani , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If sysfs isn't mounted then we may fail to read a PMU's type. In this situation resort to lookup of wellknown types. Only applies to software, tracepoint and breakpoint PMUs. Signed-off-by: Ian Rogers --- tools/perf/util/pmu.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 76b7ded7fbf4..c0c12880146a 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -1180,6 +1180,32 @@ int perf_pmu__init(struct perf_pmu *pmu, __u32 type,= const char *name) return 0; } =20 +static __u32 wellknown_pmu_type(const char *pmu_name) +{ + struct { + const char *pmu_name; + __u32 type; + } wellknown_pmus[] =3D { + { + "software", + PERF_TYPE_SOFTWARE + }, + { + "tracepoint", + PERF_TYPE_TRACEPOINT + }, + { + "breakpoint", + PERF_TYPE_BREAKPOINT + }, + }; + for (size_t i =3D 0; i < ARRAY_SIZE(wellknown_pmus); i++) { + if (!strcmp(wellknown_pmus[i].pmu_name, pmu_name)) + return wellknown_pmus[i].type; + } + return PERF_TYPE_MAX; +} + struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const= char *name, bool eager_load) { @@ -1199,8 +1225,12 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *= pmus, int dirfd, const char * that type value is successfully assigned (return 1). */ if (perf_pmu__scan_file_at(pmu, dirfd, "type", "%u", &pmu->type) !=3D 1) { - perf_pmu__delete(pmu); - return NULL; + /* Double check the PMU's name isn't wellknown. */ + pmu->type =3D wellknown_pmu_type(name); + if (pmu->type =3D=3D PERF_TYPE_MAX) { + perf_pmu__delete(pmu); + return NULL; + } } =20 /* --=20 2.50.0.rc2.696.g1fc2a0284f-goog